As the result of an unfortunate number of school shootings in which an intruder has entered a school building with a firearm or other weapon, there is a need to be able to quickly secure a classroom or other door against intrusion. Various methods have been suggested that require modifications to the building or door structures including patent application numbers US 2015/0204122 and US 2015/0137534. Other methods require the existing door latch be set to a “locked” setting and prevent the door from latching completely until the invention is disengaged (patent application numbers US 2014/0333075 and 2010/0102573). Applicable fire safety requirements are of particular concern for devices that prevent the opening of a doorway used in public buildings such as schools. In order to be compliant with many such standards, an occupant of a locked room must be able to exit the room with a single action. For example, moving a door handle to an unlocked position as the occupant presses against the doorway in order to exit. What is needed is a device for securing a doorway that can easily be added to an existing door without significant modification of the door or building structure. Such a system should not require additional components that must be added to the door during use and ideally should not require more than a single movement to engage. In order to comply with fire code requirements, the system should not require more than a single movement to open the door in the event of a fire or other circumstance in which the secured area must be evacuated.
In an embodiment of the invention, a door securing plate may be mounted to a doorknob such that the plate may rotate about the shaft of the doorknob. In such an embodiment, the rotation of the plate may be restricted by frictional interference between the shaft and the plate such that the plate will remain stationary with respect to the door to which it is attached. When desired, the door securing plate may be rotated to a point at which it extends beyond the edge of the door. In certain embodiments of the invention, when the door securing plate is in such a position, a catch device may be engaged to fix the door securing plate in position relative to the doorknob. In addition to the door securing plate and catch device, embodiments of the invention may comprise a means for capturing the door securing plate in the door frame such that when the door securing plate is rotated to the point that it extends beyond the edge of the door that it enters such a means. Thus, when the door securing plate has been rotated and is captured by the capture means, the door may be prevented from opening, securing the occupants of the room against forced or other undesired entry. In an embodiment of the invention, when the door securing plate is fixed to the doorknob, an occupant of the room need only rotate the knob in the manner ordinarily used to release the latch and allow the door to open. Because the occupant isn't required to take any additional actions to release the door for exit, such an embodiment provides a significantly increased level of safety over known designs.
Further features and advantages of the devices and systems disclosed herein, as well as the structure and operation of various aspects of the present disclosure, are described in detail below with reference to the accompanying figures.